Pump



arch 1954 M. A. KREiTCHMAN PUMP 2 Sheets-Sheet 1 Filed March 10, 194'?ATTORNEY March 9, 1954 M. A. KREITCHMAN PUMP 2 Sheets-Sheet 2 FiledMarch 10, 1947 INVENTOR' Adfiedzzzazz aiy/gyfiflil Patented Mar. 9, 1954 PUMP Morton A. Kreitchman, Irvington, N. 5., assignor toInternational Telephone and Telegraph Corporation, a corporation ofMaryland Application March 10, 1947, Serial No. 733,682

6 Claims. 1

The present invention relates to a new and novel means for retainingwater in a pump chambar and more particularly to a pump impeller in apump casing with a shaft to rotate the pump impeller and a sealing meansbetween the pump impeller and pump casing or bearing to prevent leakagefrom the pump chamber to the exterior.

In the use of washing machines, a pump mechanism having an inlet andoutlet attaches to the main washing tub of the washing machine, in anoutlet line leading from the tub, to rapidly drain the washing machineof water. The pump mechanism of the type herein described has animpeller of rubber or other resilient material. If a hard object such asbuttons, buckles, etc. enters the pump chamber, the rubber vanes of theimpeller being distortable pass over the hard object without injury tothe pump impeller. In passing over any hard objects, the impeller exertsa drag or pull on the hard object to move it to the pump outlet withoutstopping the pump action and consequently without halting the drainingof the washing machine tub.

Objects of the invention are to provide: a new seal between an impellerin a pump chamber and a shaft to rotate the impeller attached theretowith relation to a pump casing; a new sealing means for pump impellerswhich eliminates the use of stuffing boxes, packing glands or similarmeans for containing water in a pump chamber; a new combination impellerand seal arrangement whereby high sealing pressures are provided whenthe pump is not in use, which is the large percentage of the time, andthe pressure on the sealing means relieved by centrifugal force when theimpeller is rotated at high speed to thus insure a minimum wear on thesealing means during operation of the pump; a sealing means for pumpsthat is simple in construction, durable and economical; and a shaftsealing arrangement whereby an impeller shaft of ordinary material maybe employed without concern for non-corrosive qualities.

The invention includes the provision of an impeller carried on a shaftfor operation within the pump casing. The shaft extends through aninwardly projecting portion of the casing which forms a bearing for theshaft. The improvement in the present invention consists of a sealingmeans between the impeller and the bearing portion of the casing to sealthe space therebetween and about the impeller shaft. The sealing meansmay be attached to the impeller or formed as an integral part thereof inthe form of an extension of the impeller. The impeller extension ispreferably thinned or feathered so that by making the inner diameterthereof smaller than the bearing portion it may be stretched to fitsnugly thereover and thereby maintain a satisfactory seal. This sealingengagement with the bearing portion may thus be effected by eithertension of the rubber extension stretched thereover or biased by springpressure or pressure of fluid from the tub or both. A can or sleevemember may be placed over the end or sides of the bearing portion toinsure a smooth contacting surface for the impeller extension duringrotation. A metallic bushing may be embedded in the impeller to attachthe shaft to the impeller, or the shaft may be molded in the impellermaterial. Where the shaft is molded in the impeller with the seal of mpresent invention, a shaft may be selected for economic reasons withoutconcern whether or not the shaft material has non-corrosive qualities.

With the foregoing and other objects in view, the invention will be morefully described hereinafter and will be particularly pointed out in theclaims appended hereto.

In the drawings:

Figure 1 is a plan view of the pump with part of the cover broken awayto show the impeller.

Figure 2 is a sectional View through the pump casing showing one speciesof sealing means between the impeller and bearing portion;

Figure 3 is a view in perspective of the rubber impeller;

Figure 4 is a part sectional view of the pump and, another form ofsealing means; and

Figures 5 and 6 are part sectional views of the pump showing stillfurther forms of sealing means.

Figure 1 shows a pump generally represented at l includes a casing 2having an inlet 3 and an outlet i. The casing 2 has a cover plate 5 withspring latches 6 engageable with lugs 1.

An impeller 8, made of rubber or other resilient material, and havingone, two or more blades, is rotatably mounted in the casing 2. A shaft 9is rigidly connected, preferably by insert molding, to the impeller 8 atone end thereof while the other end connects with a source of motivepower (not shown). The casing 2 has an inwardly extending portion illwhich forms a bearing for the shaft 9. In Figure 2 a bearing member I Iis included between the shaft 9 and bearing portion ill of the casing.

The improvement in the present invention resides in sealing the spacebetween the pump chamber within casing 2 and the shaft 9. In

3 the figure 2, the bearing portion ID has a cap or sleeve member I2preferably of a material such as a hard wearing plastic or stainlesssteel. The impeller 8 has an annular extension 13 extending outwardly toform a socket for receiving shaft 9.

A thrust bearing [4 is disposed at the bottom of the socket for contactwith cap l2. As can readily be seen, extension I3 is feathered and fitssnugly around bearing portion It to seal the space between bearingportion and the impeller 8. When the impeller 8 is not rotating duringthe normal wash period, water from the wash tub fills inlet 3 under astatic head. In this condition the feathered rubber lip or extension I3is forced into sealing engagement with bearing portion l2 mainly due tothe tension set up in stretching the rubber lip over the bearingportion. During the drain period, the pump impeller 8 is rotated and thecentrifugal force induced by this rotation lessens the sealing pressureof the feathered rubber lip on the bearing portion 12, thus greatlyreducing wear of the sealing surfaces. A good tight seal is maintainedwhen the inlet 3 is under static head and the pump is not operating,which is the majority of the time, and when the pump is operating alighter seal pressure is realized which greatly reduces heat which wouldbe generated under the much higher pressure.

In the species of Figure 4, the bearing portion [5 has a cap member i6thereon, and the impeller I! has an integral feathered extension i8similarly as described for Figure 1 which seals with cap member 16 onthe end of bearing portion IS. A coil spring I9 is placed aroundextension [8 to force or distort the resilient extension into sealingengagement with the bearing portion 15. A second extension 2'51 integralwith impeller ll extends from the outer edge of the impeller to providea cover for coil spring 19. A metallic bushing 21 is embedded inimpeller I1 and shaft 9 is rigidly attached thereto. A flat springmember 22 is placed between bushing 2| and cap 16 to serve as a wearplate due to relative rotary motion between the two members.

Figure 5 is another embodiment similar in many respects to theembodiment shown in Figure 4. The extension 23, in this embodiment,extends coaxially of the impeller 24 and is adapted to overlie thecylindrical surface of bearing member 25 supported by portion 2E5 of thecasing. To ensure adequate sealing pressure, a coil spring 21 is placedover the extension 23.

Figure 6 shows a further variation wherein the bearing portion of thecasing is provided with an annular abutment 29 capped over with a sheetof metal 30 such as stainless steel. The impeller is provided with anannular extension 3i adapted to engage and form a seal with the metalcap 30. To ensure adequate engagement, a spring 32 is placed on theshaft 9 between bearing 34 and an abutment 35 keyed to the shaft. Thespring 32 urges the shaft in a direction to force the extension 3iagainst the metal surface 30.

While the invention has been described in connection with severalspecific embodiments, it is to be understood that the words which havebeen used are words of description rather than of limitation, and thatpractice of the invention within the scope of the appended claims may beresorted to without departing from the true scope ofthe invention in allits aspects.

I claim:

1. In a pump structure, the combination comprising: a pump having ahousing, a rotary resilient pumping element of deformable materialcooperating with the internal walls of the housing, bushing means insaid housing, said bushing means having a circular projection extendinginto said resilient pump element and encircled by said element to deformsaid material radially outward and to thereby be resiliently engaged.

2. A pump having in combination, a casing including inlet and outletports, a shaft disposed within said casing and rotatably mounted inrespect thereto, an impeller of resilient material including an annularlip portion encircling said shaft, a bearing element interposed betweensaid shaft and said lip portion, said lip portion being inherentlybiased for fluid sealing engagement with said bearing element duringimpeller actuated fluid fiow through said casing and adapted to morefirmly engage said bearing element upon static hydraulic pressurebuilt-up within said casmg.

3. A pump having in combination, a casing including inlet and outletports, a shaft partially disposed within said casing and rotatablymounted in respect thereto, an impeller of resilient material includingan annular lip portion encircling said shaft, a bearing elementinterposed between said shaft and said lip portion, said lip portionbeing inherently biased for fluid sealing engagement with said bearingelement during impeller actuated fiuid flow through said casing andadapted to more firmly engage said bearing element upon static hydraulicpressure build-up within said casing.

4. The pump of claim 3 wherein the sealing surface of said bearingelement comprises a metal offering high resistance to wear due torotation of said resilient impeller lip portion in respect thereto.

5. The pump of claim 3 wherein a bearing sleeve is interposed betweensaid bearing element and said lip portion.

6. A pump structure including a casing provided with inlet and outletports and a shaft receiving aperture, a drive shaft extending throughsaid aperture to the interior of said casing, means journaling saiddriving shaft in respect to said casing, said means including a packingmember fixed to said casing and a bearing sleeve snugly engaged betweensaid member and said shaft and including a portion extending into saidcasing beyond said packing member, an impeller of resilient materialfixedly mounted on said shaft within said casing for rotation therewithand including a hub portion provided with an axially extending annularskirt-like integral extension receivable about said sleeve element andinherently biased for light contractile engage ment with the surfacethereof, said skirt-like impeller portion being adapted to sealinglyengage said sleeve as the result of said inherent contractile biasingduring periods of fluid fiow through said casing rotation of saidimpeller and to engage said sleeve under substantially increasedpressure during periods of non-rotation of said impeller due to inwardlydirected pressure thereon resulting from increased static pressurebuild-up of fluid within said casing during said latter periods.

MORTON A. KREITCHMAN.

(References on following page) 5 References Cited in the file of thispatent Number 2,436,996 UNITED STATES PATENTS 2,439,315 Number Name Date2 4 0 952 1,764,706 Willi J111'16 17, 1930 5 2 592 91 2,021,346 AllenNov. 19, 1935 2,027,505 Winkler Jan. 14, 1936 2,245,866 McLachlan June17, 1941 Number 2,258,371 Wernert Oct. 7, 1941 497,287 2,408,909 BrummerOct. 8, 1946 10 Name Date Howser Mar. 2, 1948 Newton et a1 Apr. 6, 1948Simer et a1. Feb. 8, 1949 Atkins et a1 Apr. 4, 1950 FOREIGN PATENTSCountry Date Great Britain Dec. 16, 1937

